HyClean Pure GN vacuum cleaner bag Miele AirClean system delivers the best in filtration performance at 99.99 %. AirClean filter system. Take a breath and relax. The Miele AirClean system filters more than 99.99 % of all fine dust particles. Hygienic replacement. For hygienic bag changes. To prevent dust from getting outside, the dustbag closes automatically when the appliance is opened. Dust is securely contained. (Fine) dust remains locked in securely. Thanks to several filter layers (fine) dust that has been vacuumed up cannot escape into the room air.